When you run your website through Google PageSpeed it will highlight the Google web font script as a render blocking file.
Using the WebFontLoader to load the web fonts on the page with async and therefore removing the render-blocking on this file.
<script type="text/javascript">
WebFontConfig = {
google: { families: [ 'Roboto' ] }
};
(function() {
var wf = document.createElement('script');
wf.src = ('https:' == document.location.protocol ? 'https' : 'http') +
'://ajax.googleapis.com/ajax/libs/webfont/1.6.26/webfont.js';
wf.type = 'text/javascript';
wf.async = 'true';
var s = document.getElementsByTagName('script')[0];
s.parentNode.insertBefore(wf, s);
})();
// ]]>
</script>